This multidisciplinary research program from the Department of Human Oncology and the Wisconsin Clinical Cancer Center utilizes both laboratory and clinical programs to achieve the goal of improving therapeutic effectiveness at all stages of the disease. Individual projects are directed at: 1) developing a breast cancer specific clonal assay and evaluating its predictive efficacy for breast cancer therapy; 2) improving the overall treatment of primary breast cancer; 3) understanding the basic biology of hormone dependency and determining the mechanism of action of estrogens and antiestrogens used in the treatment of breast cancer; 4) examining specific locus mutagenesis in human breast cells; 5) use of biostatistical support and computer-based data management to facilitate research; and 6) providing appropriate administrative support to enable the research.